Beijing recently deployed the China Coast Guard (CCG) 3901 cutter, the largest in the world, into the South China Sea to protect the country's maritime rights, according to local government reports.

The vessel spent nearly three weeks patrolling islands claimed by Beijing, and its recent South China Sea tour marked its first official patrol since it was commissioned by the coast guard, the South China Sea division of China's State Oceanic Administration said.

"China prefers using its Coast Guard as the primary enforcer of its maritime claims," the Pentagon's Office of Naval Intelligence said as quoted by the Diplomat.

Dubbed as "the monster," the CCG 3901 cutter has a displacement of 12,000 tons and is bigger than the US Navy's Ticonderoga-class guided-missile cruisers and Arleigh Burke-class guided missile destroyers. The ship is also heavily armed with 76 mm rapid fire guns, two auxiliary guns, and two anti-aircraft guns.

Meanwhile, just last month, photos of an alleged CCG Type 818 vessel equipped with the Type 630 30mm close-in weapon system made rounds across the Internet. It has also been reportedly armed with a 76mm PJ-26 naval gun and installed with two turrets to defend the ship against guided munitions and hostile aircrafts.

China has been rapidly enhancing its naval capabilities, and the China Coast Guard has significantly expanded in recent years. Since 2012, China has commissioned more than 100 ships into the coast guard.

Moreover, China has also heavily relied on its coast guard and maritime militia when protecting the disputed South China Sea, carrying out "gray zone aggression" against other claimants. The CCG 3901, however, still outmatches the patrol vessels of all other claimants of the contested waterways.